stretching is actually the best exercising that one can do for your body imo. yoga of course incorporates strength moves also which makes it that much better than just stretching. i always start my morning routine stretching all muscle groups thoroughly before any cardio and or resistance training. i have never done yoga, but i end my day with stretching and tai chi, or meditation in motion as some like to refer to it as. i personally prefer tai chi because first and for most it is a martial art, and the breathing done with the postures is incredibly relaxing as well.